Hepatitis B is a viral infection that affects the liver and can become chronic. It was first described in the 5th century and major developments in understanding the virus occurred between the 1940s-1970s with the identification of antigens and viral particles. The virus is classified taxonomically and has an overlapping genome encoding various antigens. It exists in different morphological forms and has multiple genotypes and serotypes. Hepatitis B is transmitted through blood or bodily fluids and has various stages from acute to chronic infection. Diagnosis involves detecting antigens, antibodies, and viral DNA through serological and molecular tests. Vaccination and antiviral treatment can help prevent and manage the disease.
2. Introduction
• Hepatitis was first described as early as 5th century.
• First documented blood borne outbreak occurred in
Bremen, Germany in 1883.
• 1947:MacCallum and Bauer introduced the term
Hepatitis B , later adopted by WHO(1973)
• 1965:Blumberg and his coworkers described the a
protein antigen: Australia antigen
• 1970:Dane and his coworkers described the
complete Hepatitis B or Dane particle.
• 1972: Magnius and Espmark described the HBeAg.
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3. Taxonomy
• Group: Group VII(ds DNA RT)
• Order: Unassigned
• Family:
Hepadnaviridae Avihepadnaviridae Not assingned
• Genus: Orthohepadnavirus
• Species:
Hepatitis B Ground Squirrel Wood Chuck Wolly Monkey
Hepa. Hepa. Hepa.
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8. • HBsAg is antigenically complex
• Group reactive antigen- a
• Type specific antigen- d/y and w/r
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9. Typing of HBV
Serotypes
• Its divided into 4 serotypes adr, adw, ayr, ayw
Genotypes
• Eight genotypes A- H
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10. Genome
Gene Regions Antigen
S S Major protein(S) HBsAg
(Having 3 regions S,S1,Pre S2) S+ Pre S2 Middle protein(M)
S+ Pre S1& S2 Large protein(L):Present only in virion
C C HBcAg
(Having 2 regions C & Pre C) C+ Pre C HBeAg
P DNA Polymerase
X HBxAg(Not particulate antigen)
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11. Genome
• Genome is approx. 3200 base long and contains
overlapping genes.
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14. Epidemiology
• Reservoir of infection
– Cases
– Carriers
• Carriers
– Simple carriers
– Super carriers
• Prevalence
– Low endemicity- <2 %. Nepal, SriLanka
– Intermediate endemicity- 2-8%. India, bhutan,
Indonesia, Maldives
– High endemicity- >8 %. Bangladesh, korea
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15. • 2 billion people have been infected (1 out of 3
people).
• 350 million people are chronically infected.
• An estimated 6 lakh people die each year from
hepatitis B and its complications.
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16. In India
• The average estimated carrier rate of hepatitis B
virus (HBV) is 3.7%.
• An approximate total of 40 million HBV carriers
• South indians have high carrier rates
• Second most common cause of acute hepatitis after
HEV.
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17. Age
• Chance of developing acute hepatitis is directly
related to age
• 1% (perinatal)
• 10 % (early childhood)
• 30 % ( late childhood)
• Chance of developing chronic hepatitis is inversely
proportional to age
• 80-90 % (perinatal)
• 30% (early childhood)
• 5% (late childhood)
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19. Clinical manifestations
• Incubation period 30-180 days
• It is indistinguishable from other hepatitis viruses
• Pre-icteric phase- nausea, vomiting
• Icteric phase- jaundice
• Hepatic complications- fulminant hepatitis, cirrhosis,
HCC
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20. Continued…
• 4 phases
Immuno tolerance
Immuno clearance
Inactive HBsAg carrier
HBeAg – CHB
Occult Hepatitis B
Phase HBeAg serological status Pattern Indications for treatment
1. “Immune tolerant” HBeAg positive • Stage seen in many HBeAg-positive children and young
adults, particularly among those infected at birth
• High levels of HBV replication (HBV DNA levels >200 000
IU/mL))
• Persistently normal ALT
• Minimal histological disease
Treatment not generally
indicated, but monitoring
required
2. “Immune active”
(HBeAg-positivea
chronic hepatitis)
HBeAg positive; may
develop anti-HBe
• Abnormal or intermittently abnormal ALT
• High or fluctuating levels of HBV replication (HBV DNA
levels >2000 IU/mL)
Histological necroinflammatory activity present
• HBeAg to anti-HBe seroconversion possible, with
normalization of ALT leading to “immune-control” phase
Treatment may be
indicated
3. Inactive chronic
hepatitis “Immune
control”
(previously called
inactive carrier)
HBeAg negative, anti-
HBe positive
• Persistently normal ALT
• Low or undetectable HBV DNA ( HBV DNA levels <2000
IU/mL)
• Risk of cirrhosis and HCC reduced
• May develop HBeAg-negative disease
Treatment not generally
indicated, but monitoring
required for reactivation
and HCC
4. “Immune escape”
(HBeAg-negative
chronic hepatitis)
HBeAg negative, with or
without being anti-HBe
positive
• HBeAg negative and anti-HBe positive
• Abnormal ALT (persistent or intermittently abnormal)
• Moderate to high levels of HBV replication (HBV DNA levels
>20 000 IU/mL)
• Older persons especially at risk for progressive disease
(fibrosis/cirrhosis)
Treatment may be
indicated
5.“Reactivation” or
“acute-on-chronic
hepatitis”
HBeAg positive or
negative
• Can occur spontaneously or be precipitated by
immunosuppression from chemo– or immunosuppressive
therapy, HIV infection or transplantation, development of
antiviral resistance, or withdrawal of antiviral therapy
• Abnormal ALT
• Moderate to high levels of HBV replication
• Seroreversion to HBeAg positivity can occur if HBeAg
negative
• High risk of decompensation in presence of cirrhosis
Treatment indicated
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21. Collection, Transport and Storage
of Specimens
• HBV infection is diagnosed by serological and
molecular methods using serum and plasma.
• In general HBV antigens and antibodies are stable at
room temperature for several hours to days,can be
stored at 4ᴼC for months and can be frozen at -20ᴼC
to -70ᴼC for many years.
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24. HBsAg
• Appears in 1-12 weeks of infection (8-12 wks)
• Presence indicates onset of infectivity
• Becomes undetectable 1-2 months after
jaundice
• Used to calculate prevalence
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25. HBeAg and HBV DNA
• Appear shortly after appearance of HBsAg
• They are markers of-
– Active viral replication
– High viral infectivity
• They cannot differentiate stages
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27. Anti-HBc IgM
• Appears 1-2 wks after HBsAg and lasts for 3-6
month
• Indicates acute infection
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28. Anti- HBc IgG
• Appears in late stage and remains positive
indefinitely
• Chronic stage
• Carrier stage
• Recovery
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29. Total Anti HBc
• Negative indicates that a person has not been
infected with HBV.
• Indicate Acute: (HBsAg +ve; IgM Anti HBc +ve)
Resolved(HBsAg –ve)
Chronic(HBsAg +ve)
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30. Anti- HBe
• Appear after clearance of HBeAg
• Indicates diminished replication and
decreased infectivity
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31. Anti -HBs
• Appears after clearance of HBsAg remains
indifinetly
• Indicates recovery, immunity, non infectivity
• Marker of hepatitis B vaccination
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34. Microscopy
• Microscopic detection of HBV does not play a specific
role in the Diagnosis of disease.
• However liver Biopsy is typically used to assess the
extent of Histologic involvement and damage as well
as a response to therapy.
Culture
• Athough HBV can infect hepatocytes in vitro,culture
of HBV is not used for the diagnosis of infection.
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35. Antigen Detection
• A marker of active viral replication is the detection of
HBsAg and/or HBeAg during primary infection and
during Chronic HBV infection.
• Both the antigens are produced in excess by the
infected hepatocytes.
• Detected by:
ELISA
Immunochromatographic tests
Enzyme inmmunoassays Detects >=0.1ng/ml
Radio immunoassays
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36. HBsAg
• Approved by FDA for Diagnostic use only.
• Any specimen nonreactive for HBsAg are considered
negative and do not require further testing.
• Those reactive must be repeated to verify the
positive test by a Neutralization assay.
• If the neutralization assay comes negative then a
new specimen should be requested and/or a
recommendation that the patient be tested for other
markers of infection.
• Some mutant HBsAg can be missed by commercial
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38. Nucleic Acid Detection:Quantitative
• Recommended for initial evaluation of Chronic
Hepatitis B and during management, particularly in
the decision making to initiate treatment and in
therapeutic monitoring.
Criteria for Chronic HB:>=20,000IU/ml
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40. HBV genotyping
• HBV genotype potential influence the outcome of
Chronic Hepatitis B and the success of antiviral therapy.
• Genotype B has more favorable outcome than C.
• Genotyping is more important for IFN therapy as A
have more changes of seroconversion than D.
• Methods:
Genome Sequencing
RFLP
Genotype specific Amplification techniques
Hybridization techniques
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42. Biochemistry
• Serum Transaminases
ALT> AST but this reverses once Cirrhosis sets in.
• Direct and Total Bilirubin
0.3- 1 mg/100ml
• Albumin and Total protein
Albumin 4-5.5 mg/100ml
• Coagulation tests
Prothrombin time(11-12.5 sec) increases
• Alpha feto protein
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46. Treatment
• 99% previously healthy person recover and
treatment is not required
• Indicated in fulminant hepatitis or severe
chronic hepatitis
– Interferon
– Nucleoside/ nucleotide analogues- lamuvidine,
adefovir, entecavir, telbivudine, tenofovir
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47. Prophylaxis
• Recombinant subunit vaccine
• HBsAg is used as a vaccine candidate in
baker’s yeast by DNA recombinant technology
• Route- I/M
• Dosage- 10-20 μg/kg
• Schedule 0,1,6 and 6,10, 14
• Marker of protection- anti- HBs titer more
than 10 IU/ml
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48. • Booster after 5 yr for high risk group or
antibody titer falls below 10 IU/ml
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49. Passive immunisation
• HBIG should be given within 6 hrs but not
later than 48 hrs
• Dose- 0.05-.07 ml/kg
• Two doses 30 days apart
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